The pilot of a U.S. Air Force F-22 Raptor fighter jet keeps a close eye on the KC-135 refueling jet as he approaches the boom during a training mission over Nevada on July 22, 2016. Jeremy Dwyer-Lindgren, Special for USA TODAY

Gauges in the refueling pod provide critical information to the boom operator aboard a U.S. Air Force KC-135 Stratotanker, seen during a training mission over Nevada on July 22, 2016. Jeremy Dwyer-Lindgren, Special for USA TODAY

The Las Vegas Strip appears on the horizon as the crew of a U.S. Air Force KC-135 line up the runway at Nellis Air Force Base following a training mission on July 22, 2016. Jeremy Dwyer-Lindgren, Special for USA TODAY

Capt. Neil Brinkworth throttles up the number-three engine during pre-departure checks aboard a U.S. Air Force KC-135 aerial refueling jet on July 22, 2016. Jeremy Dwyer-Lindgren, Special for USA TODAY

Runway rushes by as a KC-135 Stratotanker with the U.S. Air Force, filled with 120,000 pounds of gas, takes off from Nellis Air Force Base in Nevada for a training mission on July 22, 2016. Jeremy Dwyer-Lindgren, Special for USA TODAY

Boom operator Technical Sgt. Jeremy Pratt maneuvers the jet's aerial refueling boom into position via a joystick during a training mission over Nevada on July 22, 2016. Jeremy Dwyer-Lindgren, Special for USA TODAY

Fighter jets, including the F-16 and F-22, wait their turn for gas off the wing of a U.S. Air Force KC-135 Stratotanker during a training mission over` Nevada on July 22, 2016. Jeremy Dwyer-Lindgren, Special for USA TODAY

NELLIS AIR FORCE BASE, Nev. -- It’s another bright and sunny day at Nellis Air Force Base, some twenty minutes north of downtown Las Vegas. Four U.S. Air Force KC-135 Stratotanker aerial refueling jets bake in the 120+ degree heat, as crews work to prepare them for their next mission on a recent Friday afternoon.

That mission is simple: provide gas to fighter jets taking part in one of the most realistic training war games in the world: "Red Flag." The exercise is one of the largest of its kind, spanning several weeks and involving hundreds of assets throughout the Air Force inventory.

Soon, the KC-135 Stratotanker takes off. It's loaded with 120,000 pounds of fuel; almost twice as much as a fully loaded Boeing 747.

After 40 minutes of transit, the pilots settle the jet into a pre-determined aerial refueling track at 28,000 feet over the desert. The flight pattern winds up being a giant oval, a series of left-hand turns that make it akin to a giant, aerial NASCAR track.

Once settled into the pattern, Technical Sgt. and boom operator Jeremy Pratt settles into his station in the rear of the jet. It isn’t long before the first fighters, a pair of F-22 Raptors, call in to top off their tanks.

Laying on his stomach in a claustrophobia-inducing pod that barely fit three people, Pratt gazes out the window into the sky and takes hold of a joystick, maneuvering the aircraft's 20-foot long refueling boom into position.

An F-16 fighter jet approaches the refueling boom during a training mission on Nevada on July 22, 2016.(Photo: Jeremy Dwyer-Lindgren, Special for USA TODAY)

The fighter jet appears, seemingly out of nowhere. It pulls up slowly behind the jet, gradually filling the window. A careful ballet begins as Pratt orchestrates literally connecting the two jets, now barely a stone’s throw away from one another, with the boom.

Once connected, the boom can offload as much as 1,000 gallons of gas per minute to the airplane below. By the time the flight is over, our crew will have dispensed 70,000 pounds of fuel to twelve jets in four hours. That's an unusually high number for such a mission, Pratt says.

“It’s sweaty, it’s tough work, and after every flight we’re spent,” said Pratt, adding “I’ve got the best view in the world; I love every day of it.”

As the KC-135 lumbers through the sky, it creaks and groans in ways commercial airliners don’t. And for good reason: the KC-135 happens to be one of the oldest jets in the Air Force inventory. The first Stratotanker made its inaugural flight back in 1956, during the first Eisenhower administration. Today’s jet is not much younger, having taken to the skies for the first time in 1959.

It has, however, received some tender love and care since. Upgrades in the late 1990s and again in the early 2000s removed the navigator position from the flight crew, reducing the required crew to just two pilots and the boom operator. Engines have been retrofitted several times, from the original water-injected Pratt & Whitney turbojets to today's modern high-bypass turbofans..

That hasn't necessarily made it much more pleasant for those aboard.

“Being an old jet it has its disadvantages, like no air conditioning,” said Capt. Jesus Beltran. The crew figures the temperature on board regularly exceeds 130 while they’re on the ground in Las Vegas, though it cools down once the airplane takes off.

“It’s got a lot of gremlins too,” said Beltran. “Little things that will go wrong here or there.”

Today’s flight was no exception. The auto-pilot system opted not to work, leaving Beltran’s co-pilot, Capt. Neil Brinkworth, no choice but to hand-fly the airplane for most of the four hour flight.

“Flying the KC-135 is very challenging: it’s a constantly dynamic environment,” said Brinkworth.

“She’s tried and true; I like it,” said Beltran. Plus, he adds, “there’s something to be said about flying one of the older birds. It’s pretty neat, especially when you’re flying with one of the newer jets like the F-22 Raptor. You’ve got some legacy going on.”

Despite its lengthy history, the future is expected to gradually dim for the venerable Stratotanker. Its replacement, the long-in-coming, Boeing-made KC-46 Pegasus is expected to join the fleet as early as next year.

Based on the Boeing 767 passenger jet, the KC-46 will feature a number of upgrades over the KC-135, such as the ability to fuel jets via both a boom and a drogue. Most refueling jets today are able to operate only one of the two systems at a time.
It will also do away with the otherwise sweet view that boom operators like Pratt enjoy every day. Instead of the tried and true window bay that has reigned for over 60 years, future boom operators will refuel jets via video cameras linking to a screen inside the jet; not unlike an aerial video game.

But for the crew, one of the most exciting updates might be something far simpler: reliable air conditioning.